* gnu/system/privilege.scm (file-like->setuid-program): New public
procedure.
* gnu/system/setuid.scm: Re-export it for compatibility.
(file-like->setuid-program): Remove this old version.
* gnu/services/docker.scm (singularity-setuid-programs): Use it (again).
* gnu/services/desktop.scm (enlightenment-privileged-programs): Likewise.
Change-Id: I8e41144438677a15cdadb3063651dbc780715497
* gnu/system/privilege.scm (<privileged-program>): Add a field
representing the program's POSIX capabilities.
(privileged-program-capabilities): New public procedure.
* doc/guix.texi (Privileged Programs): Document it.
* gnu/build/activation.scm (activate-privileged-programs): Take a LIBCAP
package argument providing setcap(8) to apply said capabilities.
* gnu/services.scm (privileged-program->activation-gexp): Pass said
package argument where supported. Include privileged-program-capabilities
in the compatibility hack.